Refactor PVQ codes for inter4x4
Refactor PVQ codes for inter4x4

Similarly to the refactoring of PVQ codes for 4x4 intra,
instead of calling tx and pvq_encode_helper() in 4x4 inter,
av1_xform_quant() is called.

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Change-Id: Ib69efb00ed5a5b2254478bf5db5a19d9dac12b3b

smarter/aom,luctrudeau/aom,GrokImageCompression/aom,GrokImageCompression/aom,luctrudeau/aom,smarter/aom,smarter/aom,luctrudeau/aom,GrokImageCompression/aom,GrokImageCompression/aom,luctrudeau/aom,luctrudeau/aom,GrokImageCompression/aom,smarter/aom,smarter/aom,smarter/aom,GrokImageCompression/aom,luctrudeau/aom